Electric switch



Jul 29 1924. 1,503,022

G. A. BURNHAM ELECTRIC SWITCH Filed June 27, 1921 2 Sheets-Sheet 1 'Ju ly 29 1924.

1503.022 G. A. BURNHAM ELECTRIC SWITCH Filed June 27 1921 2 Sheets-Sheet 2 Patented July 29, 1924.

UNITED STATES PATENT OFFICE.

GEORGE A. BURNHAM, OF SAUGUS, MASSACHUSETTS, ASSIGNOE, BY MESNE ASSIGN- MENTS, TO CONDIT ELECTRICAL MANUFACTURING COMPANY, A

OF MASSACHUSETTS.

CORPORATION ELECTRIC SWITCH.

Application filed June 27, 1921.

To all whom it may concern:

Be it known that I, GEORGE A. BURNHAM, a citizen of the United States, residing at Saugus, in the countyof Essex and State of Massachusetts, have invented an Improvement in Electric Switches, of which the following is a specification. 7

This invention relates to electric switches and especially to switches adapted to interrupt circuits carrying a relatively high value of current at a considerable potential.

An object of the invention is to improve the current-interrupting capacity, of the switch; and the object is attained by providing means to absorb energy developed within the switch due to an increase in internal pressure within the switch incident to circuit interruption, and automatically increase the volume of the gas expansion space of the switch whereby to keep down the pressure developed within the switch.

A further object :is generally to improve the design, construction and operation of an electric switch. I

The switch embodying the invention may include an oil receptacle, a stationarily supported or fixed frame support in the top portion of the receptacle, stationary and movable switch-members and switch-operating mechanism carried by the frame, and a movable cover spring-pressed yieldinglyv over the top of the oil receptacle having apertures therethrough through which the stationary switch members freely extend and arranged to be raised upwardly upon the occurrence of. and by an undue" pressure within the switch.

The broader features of this invention areclaimed in my Patent No..1,l13,156, issued April 18, 1922. p

Fig. 1 is a longitudinal vertical section through a switch embodying the invention.

Fig. 2 is\a plan view of the switch with the movable cover removed.

Fig. 3 is a transversevertical section taken along line 3 3 of Fig. 1. I Fig. 4 is a detail f the movable cover illustrating the meansprovided for the passage of the switch operating rods into the switch. Fig. 5 is a Fig. 4. 7

As here shown the switch section along line 5-5 of embodying the invention includes the casing or receptacle Serial No. 480,559.

operating mechanism carried thereby may be removed from the oil receptacle as a unit. Preferably said frame is narrow as compared with the width of the oil receptacle whereby to provide a substantial space on each side of the frame to admit of unrestricted gas communication between the portions of the expansion space of the switch above and below said frame.

Stationary switch members 1a are passed through apertures 15 in said frame and are secured thereto by the flanged collars 16 or other suitable means. Inasmuch as the specific switch herein chosen to illustrate the invention is adapted to control circuits of relatively high potential said switch members, which include the insulating bushings enclosing the conducting studs thereof, are relatively long and extend upward a considerabledistance above the top of the oil receptacle, and also above the cover 17 hereinafter to be described; and said switch members also diverge outwardly whereby to provide suitable air insulation between their upper terminal portions, as is common practice. Said switch members may be provided with the upper petticoat portion 14 and, preferably, said portions are made removable for a. purpose hereinafter to be ex plained.

I The switch operating mechanism is supported on said frame 11 within the switch casing; and said mechanism includes the linkages having the link 18 which is piv otally carried by the bracket 19 attached to said frame and which supports the movable switchmember 20 and guides it for vertical movement in a substantially straight line. A guide link 21 is arranged to guide the movement of said link 18 and said link 21 r gases from the switch ing the pivoted links 23 and 23 serves to operate the mechanism and said toggle is operated by the spaced, horizontally-movable rods 26L and 24* which are passed through slots 25 in the upper part of the oil receptacle. Y

The means whereby the circuit-internipting capacity of the switch is increased and energy due to circuit interruption is absorbed includes the cover 17.. Said cover is disposed over the top of and encloses the oil receptacle and the switch mechanism ar: ranged therein and may have the elevated dome 17 to provide space for the members of the switch mechanism when the movable switch member is in raised and switch closed position. Said cover is formed with a peripheral apron or flange 17 b which en closes and depends downward over the side wall of the oil receptacle 10 to guide in a downward direction oil gas expelled frointhe switch; and said flafge is prefer ably spaced from the side wall of the oil re= ceptacle to provide a vent passage A from the expansion chamber B of the switch to the atmosphere, Means are provided by which the cover is removably held yieldingly on the oil receptacle. For this purpose lugs 26 may be secured to the side wall of the oil receptacle and bolts 27 may be secured thereto and extended upwardly through apertures in lugs 17, which lugs are extended outwardly from the cover 17. Springs 28 may encircle said bolts above said cover and nuts removably threaded on said bolts may serve to press said springs against the cover. The cover may be removed from the oil receptacle by removing said nuts and springs.

Apertures 17 are formed in the top face of said cover and said stationary switchinenibers are extended therethrough to a point sufficiently above vide suitable insulation. preferably substantially than the diameter of the the cover for the double purpose of providing an insulating air gap and also clearance because of the outward divergence of the switch members above the cover, to permit the removal of the cover upwardly over the top of the switch members; and said removal may be accomplished by first removing the petticoat portions lt of the switchmembers.

In order to prevent expulsion of oil and through said apertures l7 in the cover, said apertures may be the cover to pro- Said apertures are greater in diameter switchmembers at closed to a degree sufficient to accomplish the purpose by the cover plates 30 which are disposed over the stationary switch meme hers it to be a close slidingfit thereon and said platesareor may bepressed against the inner face. of the cover and over the apertures 17 therein by the springs 31 although 'movable cover therefor obviously other means may be provided. lVith this arrangement the cover may move in a vertical direction in response to pressure conditions within the switch and the plates 30 will cover the apertures 17 in all positions of the cover. 7

The switch operating 'rods 24 and Q itare passed through slots 32 and 32 in the flange 17 of the cover, which arrangement permits movement of the cover without interference with said rods; and said slots may be closed, if desired, by the cover plate 33 which is loosely disposed in a recess 34 in the inner face of the flange 17 and between it and the side wall of the oil receptacle.

It will be seen that if a substantial pres sure is developed within the switch upon circuit interruption, the cover 17 will move upwardly against the springs 28to absorb energy due to the pressure and increase the volume of the expansion space E of the switch and so keep down the pressure; and this movement will be effected without mov-. ing or altering the relative disposition of the switchmembers and operating mechanism.

It is obvious that the invention may be embodied in other structures without departing from the spirit thereof.

I claim:

1. An electric switch having a casing, stationary and movable switch members and operating mechanism disposed within and carried by said casing, and. a movable cover free from said switch members and operating mechanism yieldingly supported on said casing.

2. An electric switch having a casing stationary and movable switch members and operating mechanism disposed within and carried by said casing, and a movable cover free from said switch members and operating mechanism having means yieldingly to support it removably on said casing.

' 8. An electric switch having a casing, stationary and movable switch-members disposed within and carried by said casing, and a movable cover free from said switchmembers and operating mechanismhaving apertures therein through which said stationary switch members are extended, and means arranged yieldingly to support said cover on said casing.

4. An electric switch having a casing, a having apertures therein, a stationary frame disposed within said casing, operating mechanism carried by said frame, r'ied by said frame and extended. freely through the apertures in said cover, and means arranged yieldingly to supportsaid cover on said casing. "j V 5. An electric switch having a casing, a movable cover therefor having apertures therein, a stationary frame removably se- Stationary switch-members carcured within said casing, operating mechanism carried by said frame, stationary switch-members supported by said frame and extended freely through the apertures in said cover, and means arranged yieldingly to support said cover removably on said casing.

6. An electric switch having a casing, a movable cover therefor having apertures therein, a stationary frame removably secured within said casing, operating mecha nism carried by said frame, stationary switch members supported by said frame and extended freely through the apertures in said cover, means to close said apertures comprising cover plates slidably disposed over said stationary switch members and said apertures, springs to press said cover plates yieldingly against the under face of said cover over said aperture, and means arranged yieldingly to support said cover removably on said casing.

7. An electric switch having a casing, a movable cover therefor having apertures therein and a peripheral flange having a slot therein depending over the side wall of said casing, a stationary frame disposed with'said casing, operating mechanism carried by said frame, stationary switch members supported by said frame and extended freely through the apertures in said casing, an operating rod extended through the slot in the flange of said cover and connected with said operating mechanism, and means arranged yield ingly to support said cover on said casin 8. An electric switch having a casing, a movable cover therefor having apertures therein and a peripheral flange having a slot therein depending over the side wall of said casing, a stationary frame disposed within said casing, operating mechanism carried by said frame, stationary switch members supported by said frame and extended freely through the apertures in said casing, an operating rod extended through the slot in the flange of said cover and connected with said operating mechanism, a plate in sliding engagement with said flange disposed over to cover the slot therein and means arranged yieldingly to support said cover on said casing.

9. An electric switch having a casing, a cover for said casing having apertures therethrough, means yieldingly to support said cover on said casing, stationary switch members extended through said cover-apertures, means disposed within said casing beneath said cover arranged to support said stationary switch members,said stationary switch members having detachable external insulat ing members which are larger than said cover-apertures.

In testimony whereof, I have signed my name to this specification.

GEORGE A. BURNHAM. 

